Some things work well for some and not for others. Cranberry juice isn't just a crank remedy, It's proven to work. Cranberry juice contains chemicals which inhibit the activity of E. coli - the bacteria most often responsible for cystitis. The chemicals - condensed tannins or proanthocyanidins - stop the bacteria sticking to mucosal surfaces lining the bladder and gut.
Alkalinising urine seems to be more effective in reducing symptoms, especially for women who are 'culture negative' - that is, no harmful bacteria can be detected in their urine.
This can be done by drinking treatments based on potassium or sodium citrate, which you can buy at the chemists. It's not clear how alkalinising the urine helps but it can quickly get rid of symptoms often without the need for antibiotics.
To maintain a healthy bladder and prevent a recurrence I take a cranberry supplement daily and touch wood..........it works.
Also known as honeymoon disease, anyone with cystitis should 'abstain' until it's cleared.
Hope this helps.